34 FORESTRY [Bot. Absts., Vol. V, 



and depth are important only in so far as these qualities affect soil moisture. Variations of 

 the root systems and the development of deep tap roots are influenced more by depth of water 

 table than by character of soil. Transpiration is also an important factor. Dr. F. von 

 Honel's experiments, which he conducted in 1S79 with 21 species, showed that the amount of 

 water transpired to produce 100 grams dry weight of leaves in various species was as follows: 

 Larch, 115 L., Ash, 98 L., Beech, 86 L., Birch, 85 L., Spruce, 21 L., Pine, 10 L. The service- 

 berry was the only species that transpired more than the larch. Kirchner describes the 

 anatomy of the larch needle as being especially adapted for aeration by the arrangement of 

 the cells length-wise in the needles, and the cell walls joined only at the corners. Air spaces 

 about the size of the cells occur between each two layers of cells. The thin cuticle of the 

 needle is also a factor. Excessive transpiration indicates the necessity of an abundant sup- 

 ply of water. The shedding of leaves in the winter is a habit necessitated by the excessive 

 transpiration. In periods of severe drought the needles turn yellow, and part of them may 

 fall to conserve moisture. The tree, however, recovers readily and new leaves develop, 

 whereas other conifers die. Specific cases were noted during the severe drought of 1911. 

 The dense parabolic crowns formed on good moist soil and the open neiloid crowns formed on 

 drier sites are so different that a division of species based on this character has been advo- 

 cated. Competition of larch with other species is largely controlled by the supply of avail- 

 able water. The fir and the spruce spread their lateral roots near the surface and, to a large 

 extent, prevent surface water from reaching the deeper soil in which the larch roots usually 

 occur. Where the larch successfully competes with other species it is due to sub-irrigation 

 of the area with water from other areas. — J. V. Hojmann. 



244. von Kunz, I. Zwanzigjahrige forstliche Betatigung eines Laien. [Twenty years' 

 forestry experience of a layman.] Schweiz. Zeitschr. Forstwesen 70: 195-200. 1919. — The 

 author is a chemist whose interest in forestry prompted him to purchase a forest meadow of 

 two hectares and plant it to tree seedlings. Spruce, fir, pine, larch, beech, oak, hornbeam 

 and elm were used. The plantation was very successful, and at the age of twenty years the 

 conifers formed a complete ground cover where they were spaced 1.25 m. by 1.25 m. The pines 

 had begun to clear, but the spruce branches were still all green. — J. V. Hojmann. 



245. von Seelen, D. Der Wald als Bruder des Feldes. [The interdependence of forest 

 and farm.] Zeitschr. Forst- u. Jagdw. 51: 308-315. 1919. — A plea for more thorough use of 

 German forest resources. A policy is outlined to accomplish this end. The war, and its 

 results, has made, it necessary for Germany to adopt a broader policy of forest management. 

 The former rather restrictive policy resulted in much waste of such natural resources as for- 

 age and nut crops within the forests, owing to the fact that grazing animals were apt to cause 

 damage to reproduction. The author argues, however, that through proper regulation such 

 damage can be minimized. Free use and administrative use policies are also outlined. Ar- 

 ticle, on whole, is an answer to an opponent to this broader concept of a forest policy. — 

 Hermann Krauch. 



246. Wahloren, A. Skogen och manniskan i forhistorisk tid. [The forest and man in 

 prehistoric times.] Skogen 6: 1-8, 65-68, 229-236. 1919. 



247. Walker, R. S. The Paulownia tomentosa tree. Amer. Forest. 25: 1485-1486. S 

 fig. 1919. 



248. Watt, A. S. On the causes of failure of natural regeneration in British oakwoods. 

 Jour. Ecol. 7: 173-203. 1919. 



249. Weir, James E., and Ernest E. Hubert. The influence of thinning on western 

 hemlock and grand fir infected with Echinodontium tinctorium. Jour. Forest. 17: 21-35. 

 1919.— See Bot. Absts. 3, Entry 574. 



